I have only loaded for my 6.8mm and was loading only in increments of .5gr of powder from the listed minimum. 10 each until I reached pressure. I'm about to load 308 for a bolt rifle I'm demanding more precision from. I'm thinking 5, five shot groups is a minimum before I can get a good idea what my load will do before I begin making adjustments. Do you more developed loaders/shooters agree?
round count for development?
- Thread starter gary55
- Start date
Google Audette ladder test and OCW load development to see very popular methods. These do not focus on group size, but a node as determined by minimal change in poi. Personally I use 2 shots per charge at 200 yards and observe clear node definition, much better than 100 yards.
OCW- a couple different links to click on from this page, it focuses on 100 yard groups and seeing where the points of impact are similar so that you can identify a stable node, ie so powder temps going up or down or a grain of powder more or less wont throw you off of your target. Then you work on seating depth to tighten up your groups http://optimalchargeweight.embarqspace.com/
Ladder test- you shoot at an extended distance, 300 yards plus, to see where different loads give you similar point sof impact which serves the same purpose as the OCW. Your looking for a group orf charge weights that all hit in the same area http://www.6mmbr.com/laddertest.html
The others have posted some good info above. To further answer your question; I like 5 shot groups for an OCW test. Most use only 3 shot groups but I like to be more certain with larger numbers incase you have a flyer. Statistics with a larger data pool tell a better story.
I use three shots as well for first round general trend gathering. Once I have figured out the broad strokes I increase it to 5 round groups for a bit more statistical assurance when narrowing in on my goal.
For my load development I load 5 of each from min to 1gr above max in .2 gr increments and shoot then across a chrono until I see pressure signs. Then I evaluate the flat spots and which one I like the best and I'm done then on to seating depth and maybe neck tension if I'm really wanting to play with it
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